M. Balooch et al., LOW-ENERGY AR ION-INDUCED AND CHLORINE ION ETCHING OF SILICON, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 14(1), 1996, pp. 229-233
Citations number
20
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
A nearly monoenergetic beam of argon and chlorine ions with kinetic en
ergy from 40 to 900 eV and intensity up to 30 mu A/cm(2) is used to st
udy the etching of Si. The etch rate and ion current density at the su
rface are simultaneously measured to obtain the etch yield. The ratio
of atomic chlorine (Cl+) to molecular chlorine (Cl-2(+)) ions striking
the surface is measured by a quadrupole mass spectrometer. In the abs
ence of any chlorine, the Ar ion sputtering of silicon at 120 eV is ab
out 0.05 silicon atoms removed per ion and monotonically increases to
1 silicon atom per ion at 800 eV. The Ar+-induced etch yield increases
by about an order of magnitude when the surface is simultaneously exp
osed to a neutral molecular chlorine flux sufficient to produce satura
tion coverages from the effusive doser. An etch yield of 0.13 silicon
atoms removed per incident Ar ion is measured at an Ar+ energy of 50 e
V, which also monotonically increases to 4 silicon atoms removed per i
ncident argon ion at 700 eV. The etch yield further increases by appro
ximately a factor of 20% as the surface is bombarded with energetic ch
lorine ions. The etch yield with energetic chlorine ions increases fro
m 0.07 to similar to 5 silicon atoms per incident ion with increasing
kinetic energy from 40 to 900 eV. (C) 1996 American Vacuum Society.